ENQ (idea)

[from the ASCII mnemonic ENQuire
for 0000101] An on-line convention for querying someone's
availability. After opening a talk mode connection to someone
apparently in heavy hack mode, one might type SYN SYN ENQ?
(the SYNs representing notional synchronization bytes), and expect
a return of ACK or NAK depending on whether or not the
person felt interruptible. Compare ping, finger, and the
usage of FOO? listed under talk mode.